In coin chute mechanisms, a number of coin sensing devices are necessary in order to assure that the coin slide cannot be pushed fully in unless the correct coin or coins are deposited. Among these sensing devices are so-called gauging dogs whose purpose is to detect the diameter of a deposited coin and prevent operation of the mechanism when a coin or the like which of too small diameter is detected. Basically, such gauging devices are in the form of levers pivotally mounted and spring biased such that a tip portion thereof may drop into the peripheral gap or space created in the coin socket by an undersize coin or bogus token as the coin slide is slid inwardly toward its operative position. In order to assure accuracy of gauging, the lever is so located that its tip describes a path of movement, relative to the slide, which intersects the coin socket nearly tangentially. In this way, even a slightly undersize bogus coin or token may be detected. However, since a bogus coin can be deposited in the coin socket so that it effectively fills the space "detected" by the tip of such dog, it is common practice to provide two dogs the respective tips of which intersect essentially tangentially with the opposite sides of the coin socket, see for example the Tratsch U.S. Pat. Nos. 1,908,380 of May 9, 1933 and 1,941,638 of Jan. 2, 1934.
Another problem involving gauging dogs is that which is encountered in those mechanisms where the denomination (and therefore diameter) of coin (or coins) may be changed to accommodate for future increase in price or cost of the goods or services provided by the structure with which the coin chute is associated. See, for example, Greenwald et al U.S. Pat. No. 4,221,285, Sept. 9, 1980. In this environment, plural gauging dogs have been required, one for each of the different diameter of the coin sockets which may be used, or if a single dog is employed, it has required complex structure which allows the dog to be adjusted in position dependent upon the size of coin socket in use, see Greenwald U.S. Pat. No. 3,763,984 of Oct. 9, 1973.
The use of coin sensing devices, including gauging dogs as above mentioned, is of course necessitated by the unfortunate fact that some users will attempt to defeat the coin chute mechanism. So-called ring dogs usually are employed to detect the presence of a washer in the coin socket. Also, it is not uncommon to employ a magnet to frustrate the user who attempts to use ferrous slugs having the proper thickness and diameter of the coin or coins to be used. Another way in which users attempt to defeat the mechanisms is to use adhesive tape over the proper coin or coins to prevent the coins from dropping into the deposit box when the coin slide is pushed in, thereby to retrieve the coin or coins when the slide is returned to its outer or "start" position.